package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.springframework.aop.framework.AopContext;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService iSeckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    @Transactional
    public Result seckillVoucher(Long voucherId) {
        // 1. 查询优惠卷
        SeckillVoucher voucher = iSeckillVoucherService.getById(voucherId);
        // 2. 判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始！！！");
        }
        // 3. 判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经开始！！！");
        }
        // 4. 判断库存是否充足
        if (voucher.getStock() < 1) {
            return Result.fail("库存不足！！！");
        }

        Long userId = UserHolder.getUser().getId();
        // 创建锁对象
        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        // 获取锁
        boolean isLock = lock.tryLock(5);
        // 判断是否获取锁成功
        if(!isLock){
            // 获取锁失败，返回错误或重试
            return Result.fail("不允许重复下单！");
        }
        try {
            // 获取代理对象 （事务）
            // 不获取代理对象执行createVoucherOrder方法，会出现@Transactional事务失效的情况
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            lock.unlock();
        }

    }

    @Override
    @Transactional
    public Result createVoucherOrder(Long voucherId) {

        // 5. 一人一单
        Long userId = UserHolder.getUser().getId();
        // 5.1 查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        // 5.2 判断是否存在
        if (count > 0) {
            return Result.fail("该用户已经购买过一次！");
        }
        // 6. 扣减库存(乐观锁，之间再判断库存是否和查到的库存一致->可以解决超卖，但会导致大多数用户下单失败，即没有其他扣减库存操作)
        boolean success = iSeckillVoucherService.update()
                .setSql("stock = stock -1")
                // where id = ? and stock = ?
                .eq("voucher_id", voucherId)
                .gt("stock", 0)
                .update();
        if (!success) {
            // 扣减失败
            return Result.fail("库存不足！！！");
        }
        // 7. 创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        // 7.1 订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        // 7.2 用户id
        voucherOrder.setUserId(userId);
        // 7.3 代金券id
        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);
        // 8. 返回订单信息

        return Result.ok(orderId);

    }
}
